The prostaglandins are a group of hormone-like substances which may be viewed as derivatives of prostanoic acid. Several prostaglandins are found widely distributed in mammalian tissue and have been isolated from this source. These prostaglandins have been shown to possess a variety of biological properties such as bronchodilation and the ability to reduce gastric secretion.
The present invention concerns PGE.sub.2 derivatives in which the 13,14-double bond (using the prostanoic acid numbering system) has been reduced. The invention also concerns certain PGE.sub.2 derivatives in which the 5,6-double bond has additionally been reduced. Further, there is an ethynyl group at the 15-position in addition to the normally present hydroxyl group. The preparation of, for example, the tris-(trimethylsilyl) derivatives of PGF.sub.2 and tetrahydro-PGF.sub.2, from which the compounds of the instant invention may readily be prepared is described in U.S. Pat. No. 3,804,889.
United States patent application Ser. No. 568,212 now U.S. Pat. No. 4,001,314 discloses, among others, 15-ethynyl-PGE.sub.2 and 15-ethynyl-PGE.sub.1. Belgian Pat. No. 805,111 discloses, among others, 13,14-dihydro,15-alkyl-PGE.sub.2. Biochemical Medicine, 11, 298 (1974) discloses 15-keto-13,14-dihydro-PGF.sub.2.alpha..